A power semiconductor device (power module) is provided with a dummy terminal that includes a shortened ground pin (GND pin) and a shortened power-supply pin, for an optimal inner structure and simple wires on a substrate. The dummy terminal is used as a “suspension lead” in an assembly step for the power module, and achieves stable manufacture.
The power module, which receives a high voltage when practically used, involves in a great rise in temperature. Thus, a fin for cooling needs to be attached to the power module in most cases. A heat dissipation fin of the power module is typically, often connected to a ground potential for use. Hence, the power module requires a high dielectric strength between its individual terminals and the fin. This holds true for the dummy terminal as well.
The terminals of the power module are each commonly made through the punching of a lead frame. Hence, the terminal sags at the side surfaces, and thus has obtuse angles at the edges of both sides. On the other hand, the terminal has, at the extremity, corners of three directions. Thus, the extremity is easily processed to have an acute angle. A terminal having a sharp portion likely, intensively receives electric fields at this sharp portion. This possibly causes degradation in dielectric strength.
Proposed are various techniques for improving the dielectric strength between the terminal and heat-dissipation fin of the power module (e.g., Patent Documents 1 and 2 below).